Azure: local id for e2e (#14432)

.azure/app-cloud-e2e.yml

@@ -17,10 +17,12 @@ pr:
   - "master"
   - "release/*"
 
+# variables are automatically exported as environment variables so this will override pip's default cache dir
 variables:
-  # variables are automatically exported as environment variables so this will override pip's default cache dir
   - name: pip_cache_dir
     value: $(Pipeline.Workspace)/.pip
+  - name: local_id
+    value: $(Build.BuildId)
 
 jobs:
   - job: App_cloud_e2e_testing
@@ -57,17 +59,18 @@ jobs:
     workspace:
       clean: all
     steps:
+
+    - script: echo '##vso[task.setvariable variable=local_id]$(System.PullRequest.PullRequestNumber)'
+      displayName: "Set id for this PR"
+      condition: eq(variables['Build.Reason'], 'PullRequest')
+
     - bash: |
         whoami
+        printf "local id: $(local_id)\n"
         python --version
         pip --version
       displayName: 'Info'
 
-    # TODO: parse the PR number
-    - bash: |
-        ID=$(date +%s)
-        echo "##vso[task.setvariable variable=local_id]$ID"
-
     - task: Cache@2
       inputs:
         key: 'pip | "$(name)" | requirements/app/base.txt'